Recap

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Recap lesson 1

• What is perception?
• Perception The process which we give meaning
• to sensory information, resulting in our own
  interpretation.
• What is Visual perception?
• Visual perception is the ability to interpret
  information and surroundings via our eyes.
• For example, when you organised the black and
  white patches into the shape of a cow
• Visual Sensation is the initial process of
  detecting and decoding environmental information
• For example When you look at the first picture
  of the cow, your eyes transmit information to
  your brain about which parts are white and which
  parts are black.

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The process of Sensationand Perception
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Eye structure and functions

• Pupil
• The opening in the centre of the iris. The size
  of the
• pupil determines the amount of light that enters
  
• the eye.
• Lens
• Transparent flexible structure in the eye that
  focuses light on the retina by changing shape
• Iris
• The coloured part of the eye. The muscles of the
  iris change the size of the pupil
• Cornea
• The front covering of the eye that covers the
  iris and pupil
• Retina
• A multi-layered sensory tissue that lines the
  back of the eye.  It contains photoreceptors that
  capture light rays and convert them into
  electrical impulses. These impulses travel along
  the optic nerve to the brain where they are
  turned into images. 

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Vision process

• Looking at your diagram, what order do you think
  the vision process occurs in? Label in pencil
  1-5.
• Cornea
• Lens
• Pupil
• iris
• Retina
• On your poster, draw arrows or write the order of
  the vision process.

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Todays objectives

• Characteristics of the visual perception system

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Visual System Characteristics - RTTOI

• Reception
• Transduction
• Transmission
• Organisation and Interpretation
• Activity Create a sentence whereby the first
  letter of each word is the visual system process
  RTTOI.
• For example, Rowan Tried To Overcome his
  Idiosyncrasies

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Reception
Reception

• Reception is the process by which the structures
  of the eye capture an image of a visual stimulus
  and focus it on the photoreceptors in the retina.
  
• There are two types of photoreceptors
• Cones Photoreceptor that responds to high levels
  of light responsible for detecting colour
  vision and fine details.
• To remember you eat ice-cream (cone included)
  during the day when its light.
• Rods Photoreceptor that responds to very low
  levels of light responsible for night vision.
• To remember you go fishing (with your rod) at
  night when it is dark.

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Transduction
Reception Transduction

• Transduction the process by which photoreceptors
  in the retina change electromagnetic energy
  (light) into electrical impulses (signals) which
  can travel along the optic nerve to the brain.
• More simply, conversion of the information into a
  form that can be processed

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Transmission
Transmission

• The process of transferring or moving info from
• one location to another. (I.e. from receptor
  cells to
• the brain)
• The optic nerve carries the visual information
  from the retina to the visual cortex which is
  located at the back of the brain specialises in
  receiving and processing visual information.

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Organisation and Interpretation
Organisation Interpretation

• Organisation
• involves assembling or arranging the features of
  a
• visual image in a meaningful way.
• For example, we perceive a house rather than
  doors, windows, walls, roof, chimney
• Interpretation
• is the process of assigning (or giving) meaning
  to visual information
• so that we can understand what we are looking at.
• For example, we know that an aeroplane doesnt
  get physically smaller as it takes off from the
  runway and flies into the sky even though it
  appears to shrink.

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• Complete Learning Activity 3.5 page 100

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VISUAL PERCEPTION PRINCIPLES

• Visual perception principles can be classified
  into
• three broad categories
• Gestalt principles
• Depth principles
• Perceptual constancies

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Gestalt Principles
Gestalt organised whole

• Gestalt principles refer to the ways in which we
  organise the features
• of a visual scene by grouping them to perceive a
  whole, complete form.
• 4 types of gestalt principles
• Figure-ground organisation
• Closure
• Similarity
• proximity

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Figure-Ground
The eye differentiates an object from its
surrounding area.
A form, silhouette, or shape is naturally
perceived as figure (object), while the
surrounding area is perceived as ground
(background).
Balancing figure and ground can make the
perceived image more clear.
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What is the figure? What is the ground
Complete your own definition of figure-ground
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Closure
Occurs when an object is incomplete or a space is
not completely enclosed.
It is the tendency to close or ignore the gaps
in stimuli, and perceive it as complete
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Write a definition for closure
What do you see?
We see three black circles covered by a white
triangle, even through it could just as easily be
three incomplete circles joined together.
Our minds react to patterns that are familiar,
even though we often receive incomplete
information
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Similarity
The principle of similarity states that things
which share visual characteristics such as shape,
size, color, texture, value or orientation will
be seen as belonging together.
It is the tendency to perceive that stimuli or
parts of a stimuli that have similar features as
one part of a whole
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What do you see?
We group together the similar objects (dark blue
circles) to perceive a number five
Write a definition for similarity
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Proximity
Proximity occurs when elements are placed close
together. They tend to be perceived as a group.
The nine squares above are placed without
proximity. They are perceived as separate shapes.
When the squares are given close proximity, unity
occurs. While they continue to be separate
shapes, they are now perceived as one group.
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Write a definition for proximity
How do you see these grouped?
Because of proximity, we see two groups, each
containing two lines of circles, rather than four
separate lines of circles.
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MINI TEST
What are these pictures examples of?
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Similarity
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Figure-ground
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Proximity
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Closure
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• Complete